Improving rice plant architecture is a promising strategy for increasing yield to meet the rising demand for rice production. The effects of modifying tiller angle, a component of plant architecture, on grain yield and dry matter production are poorly understood in rice. The objective of this study was to investigate the effects of two different alleles of , a major gene responsible for tiller angle, on rice grain yield and dry matter production. A near-isogenic line (NIL) in the genetic background of IR64, a standard rice cultivar, containing a genomic segment of chromosome 9 with the allele () from Koshihikari, a standard cultivar, and a reciprocal NIL in the genetic background of Koshihikari with the allele () from IR64 were developed. Field experiments with the NILs and parent cultivars at two different plant densities were conducted over 2 or 3 years. Introgressions of different alleles of drastically modified tiller angle regardless of genetic background. However, the introgression of into IR64 decreased grain yield and dry matter production, whereas the introgression of into Koshihikari did not affect these traits regardless of plant density. The effect on light-capture characteristics—plant canopy coverage ratio, fraction of intercepted photosynthetically active radiation, and light extinction coefficient—was greater in the comparison between IR64 and its NIL than in that between Koshihikari and its NIL. No differences in leaf dry weight, leaf area index or leaf nitrogen concentration were found in either comparison. The effects of alleles on grain yield and dry matter production via modification of light-capture characteristics differ depending on genetic background. This study demonstrated the complexity of the relationships between canopy structure and canopy photosynthesis, while emphasizing the importance of characterizing three-dimensional canopy structure in crop growth models.

中文翻译：

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Tiller Angle Control 1 两个等位基因对水稻产量和干物质生产的影响

改善水稻株型是提高产量以满足日益增长的水稻需求的一项有前景的策略。对于水稻而言，改变分蘖角度（植物结构的一个组成部分）对谷物产量和干物质生产的影响知之甚少。本研究的目的是调查 的两个不同等位基因（负责分蘖角的主要基因）对水稻产量和干物质生产的影响。标准水稻品种 IR64 遗传背景中的近等基因系 (NIL)，含有来自标准品种 Koshihikari 的等位基因 () 的 9 号染色体基因组片段，以及 Koshihikari 遗传背景中的倒数 NIL IR64 的等位基因 () 被开发出来。对 NIL 和亲本品种在两种不同植物密度下进行了 2 至 3 年的田间试验。无论遗传背景如何，显着改变分蘖角度的不同等位基因的渗入。然而，IR64 的渗入降低了谷物产量和干物质产量，而无论植物密度如何，Koshihikari 的渗入并不影响这些性状。 IR64 与其 NIL 之间的比较对光捕获特性（植物冠层覆盖率、截获的光合有效辐射分数和消光系数）的影响大于 Koshihikari 与其 NIL 之间的比较。在任一比较中均未发现叶片干重、叶面积指数或叶片氮浓度的差异。等位基因通过改变光捕获特性对谷物产量和干物质生产的影响因遗传背景而异。这项研究证明了冠层结构与冠层光合作用之间关系的复杂性，同时强调了在作物生长模型中表征三维冠层结构的重要性。